Amidst numerous discussions about reducing greenhouse gases stands a glaring question: what are the greatest sources of household emissions? To answer this, researchers at the University of California, Berkeley created this amazing interactive map that tracks the carbon footprint of all 31,000 U.S. ZIP codes. The map analyzes everything that people consume in a single year including transportation, housing, food, goods and services, and it’s a valuable tool to help cities devise localized, comprehensive climate action plans. Unsurprisingly, the researchers found that suburban sprawl accounts for a whopping 50% of the entire United States’ household carbon footprint.

The interactive map is based on a study by UC Berkeley researchers Christopher M. Jones and Daniel M. Kammen, and its findings are fascinating. Population dense cities, with smaller homes and easy access to public transport, have a lower carbon footprint than much of the rest of the country; in some cases these urban households produce 50 percent less greenhouse gases than the national average.

But there’s a sizable flip side to this: the most densely populated urban areas tend to sit within the middle of the most extensive suburbs, and these suburbs have a significantly higher carbon footprint than those urban areas. The researchers explain: “The primary drivers of carbon footprints are household income, vehicle ownership and home size, all of which are considerably higher in the suburbs,” with some suburban homes producing twice the emissions of the national average. As a result, a full 50 percent of U.S. emissions come from the suburbs, in spite of the fact that the suburbs house just 143 million of the U.S.’s 313 million residents. Overall, the low household carbon footprint of densely populated cities is, in many cases, mitigated by the footprint of surrounding suburban sprawl.

There are, of course, factors beyond income, transportation and home size that contribute to household carbon footprint (HCF). When looking at the HCF associated with energy usage, the maps show far lower emissions in the West and Northwest as compared to the Midwest and East Coast. This is due in large part to the use of low-carbon electricity sources and a growing adoption of renewable energy.

Ultimately the researchers recommend that “cities understand the size and composition of household carbon footprints in their locations and then develop customized plans that address the largest opportunities to reduce those impacts,” suggesting that “an entirely new approach of highly tailored, community scale carbon management is urgently needed.” But does this call for the end of the suburbs? The researchers don’t think so, rather that the suburbs are “ideal candidates for a combination of energy efficient technologies, including whole home energy upgrades, and solar photovoltaic systems combined with electric vehicles,” to reduce the footprint associated with suburban living.